1. Field of the Invention
The present invention relates to image formation apparatuses such as digital copy machines and printers. Particularly, the present invention relates to an image formation apparatus that limits the print operation according to additional information embedded in input image data.
2. Description of the Related Art
It is now possible to easily copy a document image by virtue of the spread of digital copy machines. Also, digital data can be printed onto a recording medium such as a sheet of paper by providing to a digital copy machine an image produced by a computer, a photograph, a picture, and digital data obtained by shooting using a digital camera.
There are cases where the digital data of a document or a computer-produced image that is to be copied is owned by the creator thereof. The creator may not wish to have the document or the digital data printed out. The concealment technique of embedding ID information or a logo as signature information into the document or digital data is known in order to prevent unlimited printing of documents and digital data.
By verifying the printed out sheet as to the image or digital data in which signature information is embedded, the document image or digital data that is the source of the printout can be identified. However, royalties associated with the printing of the image or digital data cannot be collected appropriately. An unscrupulous user can obtain a printout freely.